Check for your version of Nero in the product center.
In SmartStart in the bottom right corner click on the icon with a flame in it. Under programs what version is listed next to Nero Digital or Nero Ultra (or Premium) Edition?

this has happend twice once on fast and the furious and once on borat. but i've burned other downloaded movies before. the vidoes are good though cuz ive watched them on the computer. i tryed to find the version but when ever i click on the icon it says run time error and then closes.

That's not good. A clean reinstall of Nero may help that and the adding a file.
Uninstall Nero - run the clean tool.
Reboot. Run a good registry cleaner too like ccleaner. Use the cleaner and issues options.
Now reinstall Nero.

it burned on the disk and this time i could watch it on the computer but i can't watch it on the dvd player. i followed all the instructions on the guide thing. when i put it in the dvd it just made alot of sound and didn't do anything. i used dvd+r would there be a difference if i use -r?